Method and structure for measuring bridge induced by mask layout amendment

ABSTRACT

A method for measuring bridge induced by mask layout amendment. Provide a mask with a layout that comprises a conductor line pattern, numerous gate patterns which are connected with conductor line pattern, and numerous contact pattern groups, each contact pattern group has numerous contact patterns and at least surrounds one terminal, which does not contact with conductor line, of one corresponding gate pattern. Then, amend this layout and transfer amended layout into a substrate to form a conductor line, numerous gates and numerous contact groups in and on this substrate. Finally, electrically couple these contact groups with a terminal, then, apply an electrical signal into this conductor line and measure whether the electrical signal appears at this terminal.

This application is a Divisional of application Ser. No. 09/888,584filed Jun. 26, 2001 now U.S. Pat. No. 6,559,476.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to method, structure, and layout formeasuring bridge induced by amendment of mask layout.

2. Description of the Prior Art

Because pattern transferring process usually could not completelytransfer pattern of mask into photoresist, and because consumption isnot unavoidable during developing process and etching process. Practicalpatterns in and on substrate usually are different to patterns of mask,and following defects are unavoidable: end rounding, end shorting,corned rounding, critical dimension offset, and bridging phenomena.

Thus, in order to cancel previous defects in practical semiconductorfabrication, mask layout amendment, such as optical proximity correction(OPC), usually is performed after layout pattern is formed and beforelayout pattern is transferred. Moreover, because pattern of substrateusually is shorter/thinner than pattern of mask or is deformed, masklayout amendment usually widens/lengthens real required patterns of maskor adds auxiliary pattern(s) in neighborhood of real required patterns,to cancel the difference between substrate pattern and mask pattern, tolet substrate pattern is equal to real required pattern of mask beforemask layout pattern is performed. Furthermore, because mask pattern atleast includes numerous elements in practical semiconductor fabrication,mask layout amendment almost is performed by computer in accordance withpredetermined rule(s) and predetermined parameter(s). Hence, althoughboth rule(s) and parameter(s) could be adjusted by the operator(s), butoperator(s) could amend individual element whenever rule(s) andparameter(s) are determined.

Significantly, because critical dimension of semiconductor devices iscontinuously decreased and density of semiconductor devices iscontinuously increased, bridge (bridging phenomena) induced by amendmentof neighboring patterns also is continuously increased. Refers to FIG.1A, FIG. 1B, FIG. 1C, and FIG. 1D, which show relation between realrequired pattern 10 and amended pattern 11, where FIG. 1B is the case nobridge happens and FIG. 1D is the case bridge happens. Reasonably,because bridge is the side effect during real required pattern 10 ischanged into amend pattern 11, appearance of bridge usually could not beeliminated during sequentially pattern transferring process and etchingprocess. An then, undesired bridge usually appears in and on substrate,such as bridge between gate pattern (for forming gate) and neighboringcontact pattern (for forming contact) or bridge between gate pattern ofone transistor pattern and gate pattern of neighboring transistorpattern, and induces disadvantages such as abnormal short.

Therefore, how to certify no undesired bridge is induced by amendment ofmask layout pattern is an indispensable part of mask layout amendment.For well-known technology, because distance between neighboringtransistor is obviously larger than distance between gate and contactsof one transistor, also because gate of each transistor is obviouslyseparated from gates of other transistors for popular layout, onlybridge between gate and contacts which locates besides this gate ismeasured, refers to FIG. 2A, FIG. 2B, and FIG. 2C.

Initially, FIG. 2A shows the transistor which should be formed. Layoutof the transistor at least includes gate 21 and contacts 22, whichlocate beside gate 21 and on device area 20 of mask. To check whethersuch transistor layout could be properly formed without bridge, patternsimilar to FIG. 2A is formed on mask as FIG. 2B shows, approximated gatepattern 23 ad some approximated contact patterns 24 are formed onamended device area 205 of mask. Herein, configuration of bothapproximated gate pattern 23 and approximated contact patterns 24 isessentially similar to the configuration of both gate 21 and contacts22, but the scale and relative distance could be different. Next,pattern shown in FIG. 2B is amended, such as optical proximitycorrection, and then amended pattern is transferred into substrate 25 toform gate 26 and some contacts 27, as FIG. 2C shows. Herein, toemphasize how to measure bridge, only the case that some bridge occursfor closing gate 26 and contact 27 is shows. Afterward, electricallycouples contacts 27 with a terminal, and then applies an electric signalon gate and measure whether this electrical signal appears on thisterminal. Indisputably, electrical signal appears on terminal indicatesthat at least one contact 27 bridge with gate 26, and then it isnecessary to amended approximated gate pattern 23 and approximatedcontact patterns 24 of FIG. 2B. Of course, it also could be viewed asthis transistor layout could not be formed by current mask layoutamendment or current mask layout amendment must be improved.

Surely, amendment of FIG. 2B not only requires message(s) about whetherbridge is happened but also requires message(s) about what distancebetween gate 21 and contact 22 could prevent occurrence of bridge. Thus,as FIG. 2D shows, the popular solution is to form a mask layout patternwhich connects several stimulated gate patterns 29 by one conductor linepattern 28. Herein, each stimulated gate pattern 29 is briefly similarto, or even equal to, other stimulated gate patterns 29, and eachstimulated gate pattern 29 corresponds to several stimulated contactpatterns 295 which are located beside it. Moreover, the distance betweenone stimulated gate pattern 29 and corresponding stimulated contactpatterns 295 is different from the distance between each otherstimulated gate pattern 29 and corresponding stimulated contactpatterns. Clearly, after mask layout amendment and pattern transferringprocess, gates 26 and contacts 27 are formed on substrate 295 and arecorresponding to stimulated gate patterns 29 and stimulated contactpatterns 295. In this way, by measuring which gate 26 has bridge(s) withcorresponding contact(s) 27 and which gate 26 has no bridge withcorresponding contact 27, it is clear which stimulated gate pattern 29and corresponding stimulated contact pattern 295 could to indicate bothgate 21 and contacts 22 on mask, and could be ensure correctly patterntransfer without bridge.

However, owing to density of semiconductor devices is continuouslyincreased and layout of semiconductor devices also is continuouslyevolved, not only distance between neighboring transistors approaches tothe distance between gate and contacts of same transistor, but also gateof each semiconductor devices is closed to gates of other semiconductordevices, such as static random access memory. Thus, conventionaltechnology which only measures bridge between gate and contacts of sametransistor could not handle all possible bridge. For example, whilepattern to be formed is similar to FIG. 2A but gate 21 is longer thanFIG. 2A, as FIG. 2E shows, it is possible that terminal of gate 26 iswiden or is like a hammerheads, which usually called as endcapphenomena, although no bridge is happened. Obviously, whenever twoneighboring transistors are so closed to let they can not be separatedduring mask layout amendment, it is possible that gate of one transistorhas bridge with gate of neighboring transistor, as FIG. 2F shows. Ofcourse, FIG. 2F only shows one possible bridge, it also could be bridgebetween gate of one transistor and contact(s) of neighboring transistor,and also could be bridge between contact(s) of one transistor andcontact(s) of neighboring contact(s).

As a summary, conventional technology only could measure bridge inducedby both deformation of gate and deformation of contact(s) of sametransistor during mask layout amendment, bit could not handle bridgeinduced by other reasons. Therefore, it is desired to amend conventionaltechnology to correctly handle all possible bridge and to ensureaccuracy of mask layout.

SUMMARY OF THE INVENTION

According to previous defects of conventional technology, one mainobject of this invention is to provide a method for handling allpossible bridges.

One preferred embodiment of this invention is a method for measuringbridge induced by mask layout amendment. First, provide a mask with alayout that comprises a conductor line pattern, numerous gate patternswhich are connected with conductor line pattern, and numerous contactpattern groups, each contact pattern group has numerous contact patternsand at least surrounds one terminal, which does not contact withconductor line, of one corresponding gate pattern. Then, amend thislayout and transfer amended layout into a substrate to form a conductorline, numerous gates and numerous contact groups in and on thissubstrate. Finally, electrically couple these contact groups with aterminal, then, apply an electrical signal into this conductor line andmeasure whether the electrical signal appears at this terminal.

Another preferred embodiment is a layout for measuring deformation ofgate pattern which induced by layout amendment, at lest includes aconductor line pattern, numerous gate patterns which connects withconductor line pattern, and numerous contact pattern groups. Herein,each contact pattern group is separated with other contact patterngroups and is corresponding to one gate pattern, and has numerouscontact patterns that surround one terminal which does not contact withconductor line pattern of gate pattern.

Yet a preferred embodiment is a structure for measuring bridge betweengate and contact, at least includes gate which is located on asubstrate, dielectric layer which covers both substrate and gate,numerous contacts which are located in dielectric layer and contactedwith substrate. These contacts at least surround part of gate and eachcontact is separated from other contacts. And Conductor layer is locatedover dielectric layer and electrically coupled with contacts.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation and many of the attendant advantages willbe readily obtained as the same becomes better understood by referenceto the following detailed description when considered in connection withthe accompanying drawings.

FIG. 1A through FIG. 1D show the relation between real required patternand amended pattern, and further show the case bridge is happened andthe case bridge is not happened;

FIG. 2A through FIG. 2F are some brief illustrations for showing idea,contents, and disadvantageous of conventional technology;

FIG. 3A through FIG. 3C are some brief illustrations of one preferredembodiment of this present invention;

FIG. 4 is brief illustration of another preferred embodiment of thispresent invention; and

FIG. 5A and FIG. 5B are some brief illustration of the other preferredembodiment of this present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

By carefully analysising FIG. 2D through FIG. 2F, clearly, conventionaltechnology only considers defects induced by widen gate by measuringbridge between gate and contacts which locates beside gate, but neverconsider any defects induced by lengthen gate. Further, by comparingFIG. 2C and FIG. 2F, clearly, although conventional technology considersbridge between gate and contacts of same transistor which induced bywiden terminal of gate, conventional technology never considers anybridge between different transistors which induced by widen/lengthenterminal of gate. In other words, conventional technology nevermeasures, ever never considers, any defects induced by widen terminaland/or lengthen terminal of gate.

Aims at above problem, basic concept of this invention is to amend therelation between stimulated gate pattern and stimulated contactpatterns, or called as the relation between approximated gate patternand approximated contact patterns, such that stimulated contact patternssurround stimulated gate pattern but not only are located besidestimulated gate pattern as what conventional technology do. Moreover, inorder to handle all bridge induced by widen/lengthen terminal of gate,it is better that stimulated contact patterns surround terminal ofstimulated gate pattern, and more better that at least one stimulatedcontact pattern is closed to terminal of stimulated gate pattern or islocated in extend zone of stimulated gate pattern terminal.

To further explain concept of this invention, one preferred embodimentof this invention is a layout for measuring deformation of gate patternwhich induced by layout amendment. As FIG. 2A and FIG. 3B show, thisembodiment at lest includes conductor line pattern 31, numerous gatepatterns 32 which are located in device area 30, and numerous contactpattern groups where each has numerous contact patterns 33. Herein, eachcontact pattern group is separated with other contact pattern groups andis corresponding to one gate pattern, and has numerous contact patternsthat surround one terminal which does not contact with conductor linepattern of gate pattern.

As shown in FIG. 3A and FIG. 3B, each gate pattern 32 connects withconductor line pattern 31 and is separated with other gate patterns 32.Moreover, each contact pattern group also is separated with othercontact pattern groups, and each contact pattern groups does not touchwith any gate pattern 32. In fact, the corresponding relation betweencontact pattern groups and gate patterns 32 is one by one, and contactpatterns of one contact pattern group at least surround one terminal,which does not touch conductor line pattern 31, of gate pattern 32.

Indisputably, FIG. 3A shows the case only lengthen and/or widen terminalof gate pattern 32 is measured, and FIG. 3B shows the case that iscombination of both FIG. 3A and conventional technology. FIG. 3A clearlyemphasizes the difference between this embodiment and conventionaltechnology, and FIG. 3B apply this embodiment to measure all possiblebridges that are induced by deformation of gate pattern.

Furthermore, to ensure deformation of terminal of gate pattern 32 couldbe measured, it is better to let each contact patterns group has atleast one contact pattern 33 which is closed to terminal ofcorresponding gate pattern 32. Further, as FIG. 3C shows, wheneverterminal of gate pattern 32 which is surrounded by corresponding contactpattern group is elongated along an axis, it also is suitable to let atleast one contact pattern locate on the axis but does not touch withgate pattern 32.

Surely, this embodiment also could be applied to measure numerousdifferent transistor layout at the same time, which means shape ofdifferent gate pattern 32 could be different and/or distribution/numberof contact patterns of different contact pattern groups are different.However, as shown in FIG. 2D and corresponding discussion, in order toensure how far could avoid appearance of bridge between gate pattern 32and contact pattern group and to ensure how far could avoid bridgebetween neighboring gate patterns 32. In general, each gate pattern 32is similar to, or even equal to, to other gate patterns 32, anddistribution of contact patterns of each contact pattern group also issimilar to, or even equal to, distribution of other contact patterngroup. Herein, the distance between any gate pattern 32 and contactpatterns of corresponding contact pattern group is different to thedistance between each other gate pattern 32 and contact patterns ofcorresponding contact pattern group. For example, it is possible thatthe distance between one gate pattern 32 and one contact pattern 33,which is located closed to one terminal of this gate pattern 32 whichdoes not contact with conductor line pattern 31, of corresponding onecontact pattern group is different from the distance between each othergate pattern 32 and one contact pattern 33, which is located closed toone terminal of this gate pattern 32 which does not contact withconductor line pattern 31, of corresponding one contact pattern group.For example, it also is possible that the distance between one gatepattern 32 and one contact pattern 33, which is located beside this gatepattern 32, of corresponding one contact pattern group is different fromthe distance between each other gate pattern 32 and one contact pattern33, which is located beside this gate pattern 32 of corresponding onecontact pattern group.

Another preferred embodiment of this invention is an application offormer embodiment: a method for measuring bridge induced by mask layoutamendment. As FIG. 4 shows, this embodiment at least includes followingsteps:

As mask layout block 41 shows, provide a mask with a layout thatcomprises a conductor line pattern, numerous gate patterns which areconnected with conductor line pattern, and numerous contact patterngroups. Herein, each contact pattern group has numerous contact patternsand at least surrounds one terminal, which does not contact withconductor line, of one corresponding gate pattern. In short, mask layoutof this embodiment is the mask layer present by former embodiment.

As usual, this embodiment al least satisfies one of followinglimitations. First, contact patterns of each contact pattern grouparrange along the border of corresponding gate pattern, and each contactpattern group at least has one contact pattern located closed to oneterminal, which does not contact with conductor line pattern, of gatepattern. Second, the distance between contact patterns and correspondinggate pattern of each contact pattern group is different from thedistance of any other contact pattern group. Third, the distance betweenone gate pattern and one contact pattern, which is located closed to oneterminal of this gate pattern which does not contact with conductor linepattern, of corresponding one contact pattern group is different fromthe distance between each other gate pattern and one contact pattern,which is located closed to one terminal of this gate pattern which doesnot contact with conductor line pattern, of corresponding one contactpattern group.

As amendment block 42 shows, amend this layout. Herein, layout isautomatically amended by a computer in accordance with at lest one rulewhich is predetermined by an operator. And one popular amendment is theoptical proximity correction

As transfer block 43 shows, transfer amended layout into a substrate toform a conductor line, numerous gates and numerous contact groups in andon this substrate.

As couple block 44 shows, electrically couple these contact groups witha terminal. One popular method is to cover both gate and substrate by adielectric layer, where contact groups are not covered by dielectriclayer, and then form a conductor layer over this dielectric layer, whereconductor layer contacts with all contact groups.

As measure block 45 shows, apply an electrical signal into thisconductor line and measure whether the electrical signal appears at thisterminal or not.

Yet a preferred embodiment of this invention is a structure formeasuring bridge between gate and contact. As shown in FIG. 5A and FIG.5B, the embodiment at least includes gate 51, dielectric layer 52,numerous contacts 53, and conductor layer. Herein, in order to simplifyfigures, conductor layer is not shown in FIG. 5A and FIG. 5B, and onlypartial structure is shown.

Gate 51 is located on substrate 50. Dielectric layer 52 covers bothsubstrate 50 and gate 51, but does not cover any contact 53. Thesecontacts 53 are located in dielectric layer 52 and contacted withsubstrate 50, these contacts 53 at least surround part of gate 51 andeach contact 53 is separated from other contacts 53. Conductor layer islocated over dielectric layer 52 and electrically couples with contacts53.

As usual, contacts 53 are arranged along the border of gate 51. Also, atleast one contact 53 usually is located closed to one terminal of gate53. Further, whenever one terminal of gate 51 which is surrounded bycontacts 53 elongates along an axis, as usual at least one contact 53 islocated on the axis but is separated from gate 51.

Besides, gate 51 usually is electrically coupled with an electric sourceand conductor layer 43 usually is electrically coupled with a detector.The detector is used to measure any signal which flows from 51 gatethrough at least one conduct 52, which bridges with gate 51, intoconductor layer 53.

Obviously, structure of this embodiment could be achieved bytransferring mask layout of other two embodiments into substrate, andthen configuration of gate and contacts of this embodiment is decided byamended layout, such as amended by optical proximity correction of mask.However, this embodiment is not limited by how the structure is formed.Besides, the embodiment could be used to detect any bridge induced bygate deformation, and the embodiment does not care whether this bridgeby mask layout amendment or by mistakes of both developing process andetching process.

From the foregoing it will be appreciated that, although specificembodiments of the invention have been described herein for the purposeof illustration, various modifications may be made without deviatingfrom the spirit and scope of the invention. Accordingly, the inventionis not limited except as by the appended claims.

What is claimed is:
 1. A method for measuring bridge induced by masklayout amendment, comprising: providing a mask, said mask having alayout which comprises: a conductor line pattern; a plurality of gatepatterns, each said gate pattern being separated with other said gatepatterns, gate patterns being connected with said conductor linepattern; and a plurality of contact pattern groups, each said contactpattern group being separated with other said contact pattern groups andbeing corresponding to one said gate pattern, each said contact patterngroup at least having a plurality of contact patterns which at leastsurrounds one terminal of said corresponding gate pattern and which donot contact with said conductor line; amending said layout; transferringamended said layout into a substrate, so that a conductor line, aplurality of gates and a plurality of contact groups are formed in andon said substrate; electrically coupling said contact groups with aterminal; and applying an electrical signal into said conductor line andmeasuring whether said electrical signal appears at said terminal. 2.The method of claim 1, said contact groups being electrically coupledwith said terminal by following steps: covering both said gate and saidsubstrate by a dielectric layer, wherein said contact groups are notcovered by said dielectric layer; and forming a conductor layer oversaid dielectric layer, wherein said conductor layer contacts with allsaid contact groups.
 3. The method of claim 1, said layout being amendedby an optical proximity correction which is performed by a computer inaccordance with at lest one rule which is predetermined by an operator.4. The method of claim 1, said contact patterns of each said contactpattern group arranging along the border of corresponding said gatepattern, and each said contact pattern group at least having one saidcontact pattern being located closed to one terminal, which does notcontact with said conductor line pattern, of said gate pattern.
 5. Themethod of claim 1, the distance between said contact patterns andcorresponding said gate pattern of each said contact pattern group beingdifferent from the distance of any other said contact pattern group. 6.The method of claim 1, wherein the distance between one of said contactpatterns and the terminal of corresponding said gate pattern isdifferent from the distance between any other said contact patterns andthe terminals of any other corresponding said gate patterns.